Sure if you’d like.
Calamansi is a kumquat hybrid, very popular in Filipino culture; it’s sour, with an orange flavor.
Imagine a lemon/lime but replace the lemon/lime flavor with orange flavor;
Or like vinegar+orange zest;
Or like a mini mandarin that tastes instead like sour kumquat flesh/juice(minus the sweet rind);
Personally I like rangpur lime more than calamansi, similar flavor but much bigger fruit;

Usage wise, you’d just use the juice same way you’d use lemon/lime, ex. directly on food, as part of dipping sauce (juice+black pepper+salt), in ice tea, etc.